End cap construction

ABSTRACT

An end cap structure comprises a housing portion formed of smooth sheet material having an open portion to be covered by an end cap. The end cap has a wall portion positioned over the opening and turned edges formed around the periphery of the cap in conformity with the outer configuration of the housing being covered. The housing has a deformable surface or covering, at least in the area receiving the end cap, and at least one protuberance is formed on the turned edges, at the inner side thereof, to come into pressing contact with the deformable covering on the housing. The protuberance will cause cold flow of the covering thereby forming a dimple under the protuberance to hold the cap to the housing.

United States Patent [1 1 Edgeington, Jr.

[451 Aug. 28, 1973 END CAP CONSTRUCTION [75] Inventor: JamesNQEdgelngton, Jr.,

Albuquerque, N. Mex.

[73] Assignee: IMS Corporation, Albuquerque, N.

Mexl

[22] Filed: Dec. 27, 1971 [21] Appl. No.: 212,231

Bucek 240/51. R

An0rneyRoy H. Olson et a1.

[57] ABSTRACT An end cap structure comprises a housing portion formed ofsmooth sheet material having an open portion to be covered by an endcap. The end cap has a wall portion positioned over the opening andturned edges formed around the periphery of the cap in conformity withthe outer configuration of the housing being covered. The housing has adeformable surface or covering, at least in the area receiving the endcap, and at least one protuberance is formed on the turned edges, at theinner side thereof, to come into pressing contact with the deformablecovering on the housing. The protuberance will cause cold flow of thecovering thereby forming a dimple under the protuberance to hold the capto the housing.

8 Claims, 5 Drawing Figures PATENTED A08 28 1973 3. 7 55 666 END CAPCONSTRUCTION BACKGROUND OF THE INVENTION This invention relatesgenerally to an end cap construction and more particularly to an end capfor use with plastic coated metal housings, or the like.

Heretofore, snap-on end caps for housing structures have beenconstructed by forming turned edge portions along the periphery of theend cap. The turned edge portions are either formed by bending thematerial or by stamping or extruding a blank in a die. Aligned holes aresometimes formed in the end cap and the housing to receive a screw orrivet to secure the end cap to the housing. However, this type of endcap configuration requires accurate alignment of the holes. In manycases proper alignment is very difficult because of the thinness ofmaterial forming the housing or end cap and the possibility of shiftingof the housing configuration during use. When there is no alignment theend cap will not be held firmly in place on the housing.

Furthermore, prior art end cap structures lack esthetic appeal becauseof the need of surface distractions such as screws or dimples formedalong the turned edge portion of the end cap on the visible sidethereof.

SUMMARY OF THE INVENTION Accordingly, it is an object of this inventionto provide an end cap structure which insures exact alignment of aprotuberance with a dimple formed in the surface of the housingreceiving the end cap.

Another object of this invention is to provide an end cap structurewhich is securely fastened to housing members without the use of screwsor external dimples formed along the turned edges of the end cap.

Still another object of this invention is to provide an end capstructure which is simple and inexpensive to manufacture and efficientand reliable in use.

A feature of this invention is utilizing a housing member either totallyformed of a plastic material or having a plastic coating thereon, suchas over a sheet metal support, which plastic material or coating willcold flow under prolonged pressure.

Briefly, the end cap structure disclosed herein is shown in connectionwith a housing for a blacklight fluorescent lamp unit and is illustratedto show one preferred form of the invention. However, the end capstructure generally can be used on any housing configuration and for anysuitable purpose. Preferably the housing to receive the end cap isformed of a plastic covered sheet metal as is well known for simulatingwood grain or other textured surfaces on sheet metal such as sheetaluminum or sheet steel. Preferably, the end cap is molded plastic andhas turned edges along the periphery thereof and has a configuration toreceive the housing inwardly of the turned edges. On the inside of theturned edges is formed one or more protuberances which will engage thehousing under pressure when the end cap is applied thereto. The plasticcovering on the housing, as a result of the pressure exerted by theprotuberance, will cold flow sufficient to form a deformation in thecovering. This deformation will produce a dimple exactly under theprotuberance for perfect alignment therewith ultimately to securely holdthe end cap in position. Generally, the plastic covering on the housingwill cold flow in approximately two to five days and produce the desireddimple. However, the

length of time needed to cause cold flow of the plastic covering isdependent on, among other things, the ambient temperature and thepressure of the protuberance in contact therewith. Positioned on eachside of each protuberance is a back-up post which extends from the endcap wall and parallel to the turned edge. The sheet metal is held firmlybetween the protuberance and the back-up post to supply the properpressure to cause cold flow of the plastic covering. Preferably thebackup posts have the upper ends thereof relieved to act as guide.surfaces during application of the end cap to the housing structure.

Other objects, features and advantages of this invention will be morefully realized and understood from the following detailed descriptionwhen taken in conjunction with the accompanying drawings wherein likereference numerals throughout the various views of the drawings areintended to designate similar elements or components.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front view of a blacklightfluorescent lamp structure which has a housing for receiving a pair ofend caps in accordance with this invention;

FIG. 2 is a sectional view through line 22 of FIG.

FIG. 3 is a sectional view through line 33 of FIG.

FIG. 4 is an enlarged fragmentary view, corresponding substantially tothat of FIG. 3, but showing the plastic coating deformed to create adimple in accordance with this invention; and

FIG. 5 is a top view of the fragment shown in FIG. 4.

DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS Referring now to FIG. 1 thereis seen a light assembly designated generally by reference numeral 10.The light assembly 10 is here shown as a blacklight fluorescent lampunit used for decorative or display purposes. The light assembly 10 hasa housing 12 preferably of plastic covering metal, such plasticcoverings being of a wood or other decorative texture. A reflector unit13 is mounted within the housing and has high gloss surfaces l3a, 13band at angles relative to one another to direct the light from afluorescent lamp 14 in a given direction. While the end cap structure ofthis invention is shown in connection with the lamp assembly 10, it willbe understood that the novel aspects of this invention can beincorporated in connection with end caps for other structural devices.

Most advantageously, a pair of end caps 16 are secured to each end ofthe housing 12 and firmly held in place on the housing in accordancewith the principles of this invention. The end caps 16 preferably are ofmolded plastic construction and are fonned of any suitable moldableplastic material.

Referring now to FIG. 2, which is a section view of the end cap FIG. I,the end cap 16 has the turned edges 16a thereof surrounding the housing12. That is, the peripheral edge portion of the end cap has aconfiguration corresponding substantially to the configuration of thehousing. The housing 12 is positioned inwardly of the turned edges 16aand has a discrete elemental area thereof in contact witha plurality ofprotuberances l8 strategically located on the turned edges 16a.Positioned on each side of the protuberances 18 are back-up posts 19 and20 to hold the sheet metal of the housing 12 toward the protuberances,

As best seen in FIG. 3, the back-up posts 19 and 20 have slanted guidesurfaces 19a and 200 at the top of each post and they serve to directthe wall portion of the housing 12 between the back-up posts and. theprotuberance 18. In FIG. 3 the housing portion 12 is shown as a sheetmetal structure 120 with a plastic covering 12b. The plastic coveringpreferably is of a nature that will cold flow from pressure over aprolonged period of time, polyvinyl chloride being a preferred example.

In accordance with this invention, the protuberance 18 will then causecold flow of the plastic covering 121; immediately under theprotuberance to form a deformation 22, as seen in FIG. 4, in exactregistry with the protuberance. This deformation is a dimple in the skinof the housing and serves to hold the end cap firmly in position.

This is further shown in FIG. 5 which indicates that the deformation 22causes the wall portion of the housing 12 to move slightly toward theturned edge 16a while still maintaining the backside thereof in contactwith the back-up posts 19 and 20. Therefore, the backup posts 19 and 20are slightly urged away from the protuberance 18 upon initial insertionof the wall 12 therebetween, and after several days of constant pressureof the protuberance against the plastic covering 12!) the plasticcovering will cold flow to form the dimple.

Subsequent removal of the end cap 16 can be accomplished by exertingsufficient force to cause the protuberance to part from the dimple.Thereafter a second fastening or connecting of the end cap to thehousing 12 is readily accomplished and exact alignment of theprotuberance and dimple are achieved since the protuberance itselfcreated the dimple in the first instance.

What has been described is a simple efficient end cap structure for usein closing off a housing formed with a plastic coating or, the end capcan be used on solid plastic housings wherein the surface portion of thehousing will cold flow as described herein. Accordingly, variations andmodifications of this invention may be effected without departing fromthe spirit and scope of the novel concepts disclosed and claimed herein.Techniques for bonding polyvinyl chloride and other sheet plasticmaterial to metal are well known, and hence are not disclosed herein.Alternatively, the covering could be a coating applied to the metalrather than a discrete sheet bonded thereto.

The invention is claimed as follows:

I. An end cap structure comprising an end wall portion to be positionedover an open end of a thin wall housing, said end wall portion havingturned edges with a peripheral configuration corresponding to that ofthe housing to receive said end cap, at least one protuberance formed onsaid turned edges on the inner side thereof to come in pressing contactwith the material forming the housing, and back-up means formed on saidend wall portion adjacent said protuberance and parallel to said turnededges and positioned to receive a wall portion of the housing betweensaid protuberance and said back-up means, said back-up means beingformed by a pair of yieldable post members, each post member beinglocated on opposite sides said protuberance and spaced from said turnededges a distance to provide a space between the peripheries saidprotuberance and said pair of post members which is less than thethickness ofa wall portion of the thin wall housing inserted therein.

2. The structure of claim 1 wherein said pair of post members have guidesurfaces formed at their upper ends to guide the wall portions of thehousing between said protuberance and said back-up post members.

3. An structure for a blacklight housing containing spaced apart socketsto receive a black-light fluorescent lamp and a reflector positionedbehind the lamp and electric circuit means in the housing, to controlenergization of the lamp, said structure comprising in combination, ahousing portion formed of smooth sheet material of predeterminedthickness having an open portion to be capped, an end cap having an endwall portion to be positioned over said open portion, said end caphaving turned edges, said turned edges having a peripheral configurationto conform substantially to the outer configuration of said housingportion at the open portion thereof, said housing portion beingpositioned inwardly of said turned edges, at least one protuberanceformed on said turned edges on the inner side thereof to come intopressing contact with the smooth sheet material forming said housingportion, a pair of yieldable post members formed on said end wallportion parallel to said turned edges, each post member being locatedadjacent to and on opposite sides of said protuberance and spaced fromsaid turned edges a distance to provide a space between the peripheriessaid protuberance and said pair of post members which is less than saidpredetermined thickness of said sheet material.

4. The structure of claim 3 wherein said back-up posts have guidesurfaces formed at their upper end to insure that said sheet materialwill be directed between said protuberance and said back-up post.

5. The structure of claim 3 wherein said smooth sheet material is formedof a plastic covering over sheet metal and said plastic covering isdeformed under prolonged pressure of said protuberance.

6. An structure comprising in combination, a housing formed of smoothsheet material of predetermined thickness having an open portion to becapped, an end cap having an end wall portion to be positioned over saidopen portion, said end cap having turned edges, said turned edges havinga peripheral configuration to conform substantially to the outerconfiguration of said housing at the open portion thereof, said housingbeing positioned inwardly of said turned edges, at least oneprotuberance formed on said turned edges on the inner side thereof tocome into pressing contact with the smooth sheet material forming saidhousing, back-up means formed by a pair of yieldable post members onsaid end wall portion parallel to said turned edges, each post memberbeing located adjacent to and on opposite sides of said protuberance andspaced from said turned edges a distance to provide a space between theperipheries of said protuberance and said pair of post members which isless than said predetermined thickness of said sheet material and adeformation formed in said smooth sheet material as a result of coldflow at the surface of said material caused by the pressure contact ofsaid protuberance, whereby said deformation forms a dimple under saidprotuberance to hold said end cap to said housing.

7. The structure of claim 1 wherein said back-up posts have guidesurfaces formed at their upper end to insure that said sheet materialwill be directed between said protuberance and said back-up post.

8. The end cap structure of claim 6 wherein said smooth sheet materialis formed of a plastic covering over sheet metal and said plasticcovering is deformed under prolonged pressure of said protuberance.

1. An end cap structure comprising an end wall portion to be positionedover an open end of a thin wall housing, said end wall portion havingturned edges with a peripheral configuration corresponding to that ofthe housing to receive said end cap, at least one protuberance formed onsaid turned edges on the inner side thereof to come in pressing contactwith the material forming the housing, and back-up means formed on saidend wall portion adjacent said protuberance and parallel to said turnededges and positioned to receive a wall portion of the housing betweensaid protuberance and said back-up means, said back-up means beingformed by a pair of yieldable post members, each post member beinglocated on opposite sides said protuberance and spaced from said turnededges a distance to provide a space between the peripheries saidprotuberance and said pair of post members which is less than thethickness of a wall portion of the thin wall housing inserted therein.2. The structure of claim 1 wherein said pair of post members have guidesurfaces formed at their upper ends to guide the wall portions of thehousing between said protuberance and said back-up post members.
 3. Anstructure for a blacklight housing containing spaced apart sockets toreceive a black-light fluorescent lamp and a reflector positioned behindthe lamp and electric circuit means in the housing, to controlenergization of the lamp, said structure comprising in combination, ahousing portion formed of smooth sheet material of predeterminedthickness having an open portion to be capped, an end cap having an endwall portion to be positioned over said open portion, said end caphaving turned edges, said turned edges having a peripheral configurationto conform substantially to the outer configuration of said housingportion at the open portion thereof, said housing portion beingpositioned inwardly of said turned edges, at least one protuberanceformed on said turned edges on the inner side thereof to come intopressing contact with the smooth sheet material forming said housingportion, a pair of yieldable post members formed on said end wallportion parallel to said turned edges, each post member being locatedadjacent to and on opposite sides of said protuberance and spaced fromsaid turned edges a distance to provide a space between the peripheriessaid protuberance and said pair of post members which is less than saidpredetermined thickness of said sheet material.
 4. The structure ofclaim 3 wherein said back-up posts have guide surfaces formed at theirupper end to insure that said sheet material will be directed betweensaid protuberance and said back-up post.
 5. The structure of claim 3wherein said smooth sheet material is formed of a plastic covering oversheet metal and said plastic covering is deformed under prolongedpressure of said protuberance.
 6. An structure comprising incombination, a housing formed of smooth sheet material of predeterminedthickness having an open portion to be capped, an end cap having an endwall portion to be positioned over said open portion, said end caphaving turned edges, said turned edges having a peripheral configurationto conform substantially to the outer configuration of said housing atthe open portion thereof, said housing being positioned inwardly of saidturned edges, at least one protuberance formed on said turned edges onthe inner side thereof to come into pressing contact with the smoothsheet material forming said housing, back-up means formed by a pair ofyieldable post members on said end wall portion parallel to said turnededges, each post member being located adjacent to and on opposite sidesof said protuberance and spaced from said turned edges a distance toprovide a space between the peripheries of said protuberance and saidpair of post members which is less than said predetermined thickness ofsaid sheet material and a deformation formed in said smooth sheetmaterial as a result of cold flow at the surface of said material causedby the pressure contact of said protuberance, whereby said deformationforms a dimple under said protuberance to hold said end cap to saidhousing.
 7. The structure of claim 1 wherein said back-up posts haveguide surfaces formed at their upper end to insure that said sheetmaterial will be directed between said protuberance and said back-uppost.
 8. The end cap structure of claim 6 wherein said smooth sheetmaterial is formed of a plastic covering over sheet metal and saidplastic covering is deformed under prolonged pressure of saidprotuberance.